457
FXUS63 KILX 060001 CCA
AFDILX

Area Forecast Discussion...CORRECTED
National Weather Service Lincoln IL
Issued by National Weather Service St Louis MO
701 PM CDT Thu Jun 5 2025

.KEY MESSAGES...

-Despite daily rain chances through Monday, most of central
 Illinois will experience below normal rainfall over the next 7
 days. The exception will be in areas near and south of I-70 where
 there is a chance (30-50%) for above normal rainfall. Normal
 rainfall this time of year is about 1 inch per week.

-Temperatures are trending slightly below normal over the next 7
 days with afternoon highs generally in the 70s and overnight lows
 around 60. The normal high this time of year is around 82 F.

-Any storms that do develop between now and Monday have a low
 risk (< 5% probability) of severe weather and/or flash flooding.

&&

.DISCUSSION... (Through next Thursday)
Issued at 233 PM CDT Thu Jun 5 2025

Choppy mid-level, zonal flow will support daily chances for rain
through Monday across portions of central and southeast Illinois.
The coverage of such activity looks to be confined to areas near
and south of I-70 on Friday, then areawide Saturday, Sunday and
Monday. On the synoptic scale, any showers and storms that develop
Friday and Saturday will be tied to a shortwave impulse and its
attendant sfc low pressure (if not decaying MCV) that will ride
along a diffuse baroclinic zone. The Sunday activity will be
driven by a weak synoptic cold front that slumps across the region
later in the evening. And then any showery activity that bleeds
into Monday afternoon will be scattered, stratocu-type rain on the
backside of a departing upper-level low. On the whole, CAPE/Shear
profiles during this stretch appear underwhelming and not
supportive of severe weather. The sneaky exception could be Friday
and Saturday afternoon, particularly if a squirrelly MCV does in
fact traverse our southern counties.

The rain chances and associated cloud cover should keep a
downward pressure on temperatures through early next week, with
NBM guidance offering afternoon temps in the 70s and overnight
lows around 60. Certainly we will breach 80 in a few spots during
this stretch given a favorable summer sun angle, but it should be
the exception and not the rule.

A brief stretch of dry and seasonably hot weather is apparent
among blended (NBM) and ensemble guidance (LREF) for Tuesday and
Wednesday. By then, the upper low will begin to open and lift out
of the Great Lakes region, and a ridge of surface high pressure
will build across the central US. A little bit of noise creeps
back into the guidance by Thursday, with some (GEFS) signaling a
return of rain while others (EPS/GEPS) fade it.

MJA

&&

.AVIATION...  (For the 00z TAFs through 00z Friday Evening)
Issued at 659 PM CDT Thu Jun 5 2025

Areas of haze and decreasing MVFR ceilings have resulted in a
mixture of MVFR and VFR flight conditions that should persist
through the evening, before decreasing clouds allow the development
of areas of fog and low stratus overnight into Friday morning. IFR
flight conditions are most likely at KSPI, KDEC, and KCMI with the
lowest ceilings and visibility. Dense fog also cannot be ruled out.
On Friday, fog and low stratus will start to lift during the morning
with improving flight conditions to VFR by around midday. However,
there is the potential for showers and a few rumbles of thunder to
lift into the region during the afternoon, with the greatest chance
at KSPI.

Pfahler

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$